1. Field of the Invention
The invention relates to a membrane valve, particularly for fluid media, having a valve body, a membrane, a pressure piece and a drive for the pressure piece, wherein the membrane is coupled to the pressure piece by of a connecting element, wherein the connecting element comprises a wall projecting from the membrane in the direction of the pressure piece, wherein a laterally projecting latch hook is provided on one side of the wall and on the other side is provided a free space, so that the wall can get out of the way for connecting the latch hook with a corresponding receptacle.
2. Description of the Related Art
There are known membrane valves that have a valve body having an inflow and an outflow (DE 20 2005 002 152 U1). Furthermore, the valve bodies comprise a valve seat sealable by a membrane, wherein the membrane is connected by a connecting element with a pressure piece of a drive. The known membranes can be made in one or two layers. From WO 2010/025 905 A1 is known a single-layer membrane, which may also be formed integrally with the connecting element or on which can be formed the connecting element. The membrane is made of the same plastic material as the valve body, namely of polyethylene (PE). In addition, the valve body and the membrane are connected fixedly to each other by ultrasonic welding in a fluid-tight valve body unit which can be coupled with the drive.
Due to the fixed connection of the valve body, the membrane and the connecting element to a sealed valve body unit, it is possible to form the valve body unit as a disposable unit, and to integrate the membrane valve into a disposable hose system or pre-sterilizable pharmaceutical system. The valve body unit can therefore be formed in a cost-effective way as a disposable or single-use valve body unit and be coupled to a reusable drive or connected to it. The firm connection of the membrane and the valve body seals the valve body unit during the transport phase. This avoids contamination of the valve chamber or the environment.
Due to the firm connection of the connecting elements with the membrane, the membrane can not only be pushed into its closed position but also pulled into its open position, so that the valve chamber in the valve body can be designed to be relatively large in volume and thereby, for example, a sufficiently large volume flow can be achieved for the tube systems of filtration equipment. However, it has turned out that the achievable lift between the closed and open positions is limited, because otherwise the coupling of the pressure piece and the connecting element is unintentionally released as the connecting element disengages due to too high pressure.